Valve opening/closing timing control device

ABSTRACT

A valve opening/closing timing control device includes: a driving side rotational member; a driven side rotational member; a retarded angle chamber and an advanced angle chamber; a lock mechanism; and a spiral spring providing a biasing force in a predetermined phase direction in a retarded angle region of a relative rotational phase of the driven side rotational member to the driving side rotational member from a most retarded angle phase to a predetermined phase, and not providing the biasing force to a most advanced angle phase from the predetermined phase.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. §119 toJapanese Patent Application 2009-222386, filed on Sep. 28, 2009, theentire content of which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to a valve opening/closing timing control devicecapable of adjusting the opening/closing timing of the intake valves orexhaust valves of an internal combustion engine used in vehicles such asautomobile, and more particularly to a valve opening/closing timingcontrol device including a driving side rotational member synchronouslyrotatable with a crankshaft, a driven side rotational member arrangedcoaxially with the driving side rotational member in a relativelyrotational manner and integrally rotatable with a camshaft that opensand closes valves of an internal combustion engine, a retarded anglechamber and an advanced angle chamber which are formed by the drivingside rotational member and the driven side rotational member, in whichthe retarded angle chamber moves a relative rotational phase of thedriven side rotational member to the driving side rotational member in aretarded angle direction, and the advanced angle chamber moves therelative rotational phase of both rotational members in an advancedangle direction, and a lock mechanism confining the relative rotationalphase to a predetermined lock phase, specifically, a technique forbiasing the driving side rotational member and the driven siderotational member in a direction of a lock phase.

BACKGROUND DISCUSSION

JP-A-2000-345816 (Patent Document 1; paragraphs [0057] to [0067], andFIGS. 1, 2, 3 and 6) discloses a valve opening/closing timing controldevice including a driving side rotational member (a shoe housing inPatent Document 1) and a driven side rotational member (a vane rotor inPatent Document 1), in which an accommodation chamber is divided intotwo parts, an advanced angle chamber and a retarded angle chamber, by avane provided on the driven side rotational member. The valveopening/closing timing control device further includes a fitting typerestriction means for setting a phase difference between the drivingside rotational member and the driven side rotational member to anoptimum intermediate position, and a spring as an advanced angle meansfor rotating the driven side rotational member with respect to thedriving side rotational member in the advanced angle direction. One endportion of the spring is locked to a locking hole of the driving siderotational member, and the other end portion of the spring is locked toa locking hole of an elongated hole shape (second embodiment).

With the above configuration, if the engine starts up in a state inwhich the driven side rotational member (camshaft side) is more to theretarded angle side than an intermediate position, the driven siderotational member is rotated in the direction of the intermediateposition by the biasing force of the spring to fit the restrictionmeans, and thus the engine starts up quickly. After the engine startsup, operating oil is supplied to the restriction means to release thefitting, and the operating oil is supplied to any one of the advancedangle chamber and the retarded angle chamber to achieve a relativerotation between the driving side rotational member and the driven siderotational member.

In Patent Document 1, when the driven side rotational member isrelatively rotated toward the advanced angle side with respect to thedriving side rotational member by releasing the fitting of therestriction means, the other end portion of the spring is moved in theengaging hole with the elongated hole shape, so that the biasing forceof the spring does not act.

Further, a valve opening/closing timing control device disclosed inJP-A-2009-074384 (Patent Document 2; paragraphs [0026] to [0028], andFIGS. 3 to 7) includes a driving side rotational member and a drivenside rotational member, in which an accommodation chamber is dividedinto two parts, an advanced angle chamber and a retarded angle chamber,by a vane provided on the driven side rotational member. The valveopening/closing timing control device further includes a lock mechanismfor fixing and maintaining the driving side rotational member and thedriven side rotational member to an intermediate lock phase, and atorsion spring to bias the driving side rotational member and the drivenside rotational member in the direction of the intermediate lock phasewhich generates an assisting force.

The torsion spring serves to suppress displacement of the retarded angleside in a region between an intermediate regulation phase which isplaced in the direction of the retarded angle phase than theintermediate lock phase, and a most retarded angle phase, and has therole of a stopper at the displacement from the intermediate lock phaseto the intermediate regulation phase after the engine starts up.

In Patent Document 2, one end portion of the torsion spring is fixed tothe driving side rotational member, and the other end portion can abutagainst an opening formed diametrically in the driven side rotationalmember. A spring receiving groove to which the other end portion isinserted is formed in the driving side rotational member. As the otherend portion of the torsion spring abuts against an abutting surface ofthe opening in an effective range between the intermediate regulationphase and the most retarded angle phase by the configuration, thebiasing force acts on the driven side rotational member. Further, theother end portion abuts against a stopper surface of the springreceiving groove in the intermediate regulation phase, so that nobiasing force acts on the driven side rotational member.

As disclosed in Patent Document 1 or Patent Document 2, the torsionspring is used between the driving side rotational member and the drivenside rotational member as the biasing means for biasing the rotationalmembers in the direction of the lock phase from the most retarded anglephase. The number of turns in a coil portion of the torsion spring isrequired to some degree, thereby causing the whole valve opening/closingtiming control device to become larger.

That is, so as not to vary spring load significantly in the relativerotational region of the driven side rotational member with respect tothe driving side rotational member from the most retarded angle phase tothe lock phase, the number of turns in the coil portion is required tosome degree. Therefore, there is a need for a space in the direction ofa shaft core by a dimension corresponding to the number of turns, whichcauses the whole valve opening/closing timing control device to becomelarger.

A need thus exists for a valve opening/closing timing control device isnot susceptible to the drawback mentioned above.

SUMMARY

According to an aspect of this disclosure, there is provided a valveopening/closing timing control device including a driving siderotational member synchronously rotatable with a crankshaft of aninternal combustion engine, a driven side rotational member arrangedcoaxially with the driving side rotational member in a relativelyrotational manner and integrally rotatable with a camshaft that opensand closes valves of the internal combustion engine, a retarded anglechamber and an advanced angle chamber which are formed by the drivingside rotational member and the driven side rotational member, in whichthe retarded angle chamber moves a relative rotational phase of thedriven side rotational member to the driving side rotational member in aretarded angle direction in accordance with volume increase, and theadvanced angle chamber moves the relative rotational phase in anadvanced angle direction in accordance with volume increase, a lockmechanism confining the relative rotational phase to a predeterminedlock phase, and a spiral spring providing a biasing force in apredetermined phase direction in a retarded angle region of the relativerotational phase from a most retarded angle phase to a predeterminedphase of the driven side rotational member to the driving siderotational member, and not providing the biasing force to a mostadvanced angle phase from the predetermined phase.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and additional features and characteristics of thisdisclosure will become more apparent from the following detaileddescription considered with the reference to the accompanying drawings,wherein:

FIG. 1 is across-sectional view illustrating a valve opening/closingtiming control device including an electromagnetic control valve;

FIGS. 2A and 2B are cross-sectional views taken along the line IIa-IIaand the line IIb-IIb in FIG. 1 in a most retarded angle phase;

FIGS. 3A and 3B are cross-sectional views illustrating an outer rotorand an inner rotor at a lock phase, and a spiral spring at the lockphase;

FIGS. 4A and 4B are cross-sectional views illustrating the outer rotorand the inner rotor at a most advanced angle phase, and the spiralspring at the most advanced angle phase; and

FIG. 5 is a perspective view illustrating the shape of the spiralspring.

DETAILED DESCRIPTION

Embodiments disclosed here will now be described with reference to theaccompanying drawings.

(Basic Configuration)

As shown in FIG. 1 and FIGS. 2A and 2B, a valve opening/closing timingcontrol device includes an outer rotor 1 serving as a driving siderotational member and synchronously rotatable with a crankshaft (notshown) of an engine (an internal combustion engine), an inner rotor 2serving as a driven side rotational member and coaxially andsynchronously rotatable with a camshaft 3 which opens and closes anintake valve or an exhaust valve in a combustion chamber of the engine,and an electromagnetic control valve V.

The valve opening/closing timing control device includes a configurationin which the inner rotor 2 (driven side rotational member) is insertedin the outer rotor 1 (driving rotational member). Consequently, theouter rotor 1 and the inner rotor 2 can be relatively freely rotatedaround a core X of a rotational shaft in the range of a predeterminedrelative rotational phase. A fluid pressure chamber is formed betweenthe outer rotor 1 and the inner rotor 2, the fluid pressure chamber ispartitioned into a retarded angle chamber 11 and an advanced anglechamber 12 by a vane 5 installed therein.

The vane 5 is inserted into a vane groove formed in the outercircumference of the inner rotor 2, and is biased in a protrudingdirection by a leaf spring. Consequently, at the time of relativerotation of the outer rotor 1 and the inner rotor 2, an outer endportion of the vane 5 is slidable on an inner surface of the outer rotorin the fluid pressure chamber.

The camshaft 3 is coaxially arranged with the core X of the rotationalshaft. The camshaft 3 is connected to the inner rotor 2 by a connectingbolt 4. A front plate 6 is placed on one surface of the outer rotor 1,and a rear plate 7 is placed on the other surface of the outer rotor 1.The front plate 6 and the rear plate 7 are fixed to the outer rotor 1 bya plurality of fixing bolts 8. With the configuration, the inner rotor 2is interposed between the front plate 6 and the rear plate 7.

Further, the front plate 6 includes a spiral spring S to provide abiasing force on the outer rotor 1 (driving side rotational member) andthe inner rotor 2 (driven side rotational member), and a cover 9 tocover the spiral spring. The detailed configuration of the spiral springS will be described below.

A timing sprocket 7S is integrally installed on the outer circumferenceof the rear plate 7. Between the timing sprocket 7S and a gear attachedto the crankshaft of the engine, there is provided a power transmissionmember (not shown) such as a timing chain or a timing belt.

In the configuration, upon start-up of the engine, a rotational drivingforce of the crankshaft is transmitted to the timing sprocket 7S throughthe power transmission member, and the outer rotor 1 rotates in arotational direction T shown in FIG. 2A or the like. As the inner rotor2 rotates in the rotational direction T in conjunction with therotation, the camshaft 3 rotates, and the intake valve or the exhaustvalve of the engine is opened or closed by the driving rotation of a cam(not shown) provided on the camshaft 3.

In the valve opening/closing timing control device, when the engineoperates, if the advanced angle chamber 12 is supplied with operatingoil, the volume of the advanced angle chamber 12 is enlarged by thepressure acting on the vane 5, and thus the inner rotor 2 is moved in adirection denoted by an arrow T1 with respect to the outer rotor 1.Consequently, the relative rotational phase of the outer rotor 1 and theinner rotor 2 is shifted in the advanced angle direction. In contrast,if the retarded angle chamber 11 is supplied with the operating oil, thevolume of the retarded angle chamber 11 is enlarged by the pressureacting on the vane 5 in an adverse direction, and thus the inner rotor 2is moved in a direction denoted by an arrow T2 with respect to the outerrotor 1. Consequently, the relative rotational phase of the outer rotor1 and the inner rotor 2 is shifted in the retarded angle direction. Theopening and closing timing of the intake vale or exhaust valve iscontrolled by changing a rotational phase of the camshaft 3 with respectto the rotational phase of the crankshaft.

Engine oil is used as the operating oil, and the valve opening/closingtiming control device includes a lock mechanism L to maintain therelative rotational phase between the outer rotor 1 and the inner rotor2 at a lock phase suitable for the start-up of the engine. In otherwords, the lock mechanism L restricts the relative rotation between theouter rotor 1 and the inner rotor 2 when the relative rotational phasebetween the outer rotor 1 and the inner rotor 2 becomes thepredetermined phase, i.e., the predetermined lock phase. The lockmechanism L confines (locks) the outer rotor 1 and the inner rotor 2 ata set relative rotational phase in circumstances in which the pressureof the operating oil is an unstable state immediately after the start-upof the engine. Therefore, the rotational phase of the camshaft 3 withrespect to the rotational phase of the crankshaft is maintained at aphase suitable for the start-up of the engine, thereby providing thestable start-up of the engine.

The lock mechanism L is constituted of a pair of lock pieces 14 of aplate shape extendable and withdrawing freely to and from the outerrotor 1, a spring 15 biasing each of the lock pieces 14 in a protrudingdirection (direction of the inner rotor 2), and a pair of lock concaveportions 16 formed on the outer circumferential portion of the innerrotor 2 in a concave shape so as to be engaged to each of the lockpieces 14. In this instance, as the shape of the lock pieces 14, a pinshape may be employed, as well as the plate shape shown in thisembodiment.

In the valve opening/closing timing control device, the inner rotor 2 isprovided with a retarded angle chamber side oil passage 11 a throughwhich the operating oil is distributed to a plurality of retarded anglechambers 11, an advanced angle chamber side oil passage 12 a throughwhich the operating oil is distributed to a plurality of advanced anglechambers 12, and a lock release oil passage 16 a through which theoperating oil is distributed to the lock concave portion 16.

As shown in FIG. 1 and FIGS. 2A and 2B, the cam shaft 3 is fitted with abush 18, and the bush 18 is relatively rotated with respect to thecamshaft 3. There is an oil passage system to supply sequentially theoperating oil to an internal oil passage 3 a of the camshaft 3 and aninternal oil passage 2 a of the inner rotor 2 from a supply oil passage18 a of the bush 18. The operating oil supplied from a hydraulic pump Pto the supply oil passage 18 a is supplied to a cylindrical space 2S ofthe inner rotor 2 by the oil passage system. Further, the operating oilsupplied to the inner rotor 2 is supplied to the retarded angle chamberside oil passage 11 a, the advanced angle chamber side oil passage 12 a,and the lock release oil passage 16 a by the electromagnetic controlvalve V, and is discharged from the retarded angle chamber side oilpassage 11 a, the advanced angle chamber side oil passage 12 a and thelock release oil passage 16 a by the electromagnetic control valve V.

(Electromagnetic Control Valve)

The electromagnetic control valve V includes an operating oil controlportion Va having a spool valve 22 which is operated by anelectromagnetic solenoid 21, and an operating oil supply/dischargeportion Vb of a cylindrical shape to perform distribution of theoperating oil, in which the operating oil control portion and theoperating oil supply/discharge portion are integrally formed. Theoperating oil supply/discharge portion Vb includes a check valve Cprovided in a main oil passage 23 to receive the operating oil from theabove-described inner oil passage 2 a. In an entire circumference of anouter surface of the operating oil supply/discharge portion Vb, threeports 24, 25 and 26 are formed in a groove shape, in which thedistribution of the operating oil is controlled by the spool valve 22.An oil seal 27 is fitted from outside on the outer circumference of theoperating oil supply/discharge portion Vb to suppress leakage of theoperating oil from each of the ports 24, 25 and 26.

The above-described cylindrical space 2S is formed in the inner rotor 2so as to form a cylindrical shape around the core X of the rotationalshaft, and the above-described operating oil supplying/dischargingportion Vb of the electromagnetic control valve V is relativelyrotatably fitted in the cylindrical space 2S. In this instance, theretarded angle chamber side oil passage 11 a, the advanced angle chamberside oil passage 12 a and the lock release oil passage 16 a are incommunication with the ports 24, 25 and 26 in the figure, but therelative disposition of the oil passages is not limited thereto.

In the valve opening/closing timing control device, a gap is formedbetween the inner rotor 2 and the front plate 6 and between the innerrotor 2 and the rear plate 7, in which the operating oil slightly leaksthere through. The operating oil slightly leaks through the othermovable portion. The leaked operating oil is collected by an oil pan(not shown).

(Outline of Control System)

Although not shown in the figures, the control system of the valveopening/closing timing control device includes a crank angle sensordetecting the rotational angle of the crankshaft of the engine, acamshaft angle sensor detecting the rotational angle of the camshaft 3,and an ECU (not shown) controlling the electromagnetic control valve V.

The ECU is provided with a signal system acquiring ON/OFF information ofan ignition key, information from an oil temperature sensor detectingthe temperature of the engine oil, or the like, and control informationof the optimum relative rotational phase according to the driving stateof the engine is stored in a nonvolatile memory.

The ECU detects the relative phase of the outer rotor 1 and the innerrotor 2 based on information of the driving state (e.g., revolutions ofengine, temperature of cooling water or the like) and the detectedresult of the above-described crank angle sensor and camshaft anglesensor. The distribution of the operating oil to the retarded anglechamber side oil passage 11 a, the advanced angle chamber side oilpassage 12 a and the lock release oil passage 16 a is performed byoperating the electromagnetic control valve V based on the information,thereby controlling the relative rotational phase of the outer rotor 1and the inner rotor 2. Consequently, the phase control is achievedbetween the most retarded angle phase (relative rotational phase inwhich the volume of the retarded angle chamber 11 is maximized) and themost advanced angle phase (relative rotational phase in which the volumeof the advanced angle chamber 12 is maximized), and the lock state andthe unlock state by the lock mechanism L are achieved.

If an operation is performed to stop the engine, the ECU moves therelative phase of the outer rotor 1 and the inner rotor 2 in the lockphase direction by supplying the operating oil to the retarded anglechamber 11 or the advanced angle chamber 12 in a state in which theoperating oil is discharged from the lock release oil passage 16 a.Consequently, the engine stops in a state in which the pair of lockpieces 14 is engaged to the pair of the corresponding lock concaveportions 16. When the engine starts up after stopping, the engine startsup reliably by confining (restricting) the outer rotor 1 and the innerrotor 2 with the lock mechanism L to hold the relative rotation (to thepredetermined lock phase).

After the start-up of the engine, the ECU supplies the operating oil tothe lock release oil passage 16 a to lift the lock pieces 14 up from thelock concave portions 16 to thereby release the lock. The ECU changesthe relative phase of the outer rotor 1 and the inner rotor 2 in a statein which the pressure of the operating oil acts on the lock release oilpassage 16 a, so that the control of the opening and closing timing ofthe intake valve and the exhaust valve is performed by the ECU.

In a case where the inner rotor 2 with respect to the outer rotor 1 isin the retarded angle side region than the lock phase, theabove-described spiral spring S has a function of providing the biasingforce in the lock phase direction (direction of the predetermined phase)with respect to the inner rotor 2. Therefore, a problem in which therelative phase of the inner rotor 2 integrally rotating with thecamshaft 3 is retarded with respect to the rotation of the outer rotor 1since the camshaft 3 receives resistance from the valve spring issolved.

In a case where the engine is in the stop state since excessive load isapplied to the engine, the inner rotor 2 may reach the most retardedangle phase with respect to the outer rotor 1. When the engine starts upin this situation, the ECU controls the phase of the inner rotor 2 withrespect to the outer rotor 1 to move to the lock phase early and thusset the phase in a lock state so as to perform reliable start-up of theengine.

As a detailed control mode, the electromagnetic control valve Vdischarges the operating oil from the lock release oil passage 16 a,discharges the operating oil from the retarded angle side oil passage 11a and supplies the operating oil to the advanced angle chamber side oilpassage 12 a by the control of the ECU, so that the inner rotor 2 withrespect to the outer rotor 1 is moved in the lock phase direction. Underthe control, the lock pieces 14 are engaged to the lock concave portions16 at the timing in which the outer rotor 1 and the inner rotor 2 reachthe lock phase, so that the lock mechanism L is in the lock state. Inthis instance, the rotational phase of the most retarded angle phase, inwhich the inner rotor 2 is disposed at the most retarded angle side, isreferred to as a super-retarded angle phase.

However, in a case in which the engine starts up in the state in whichthe inner rotor 2 is at the most retarded angle phase, the time isneeded until the relative rotational phase reaches the lock phase, sothat the start-up of the engine is not smoothly performed. Inparticular, the operating oil is cold at the time of stopping the enginein cold climates, the viscosity of the operating oil is high, and thusthe distribution of the operating oil to each of the retarded anglechamber 11 and the advanced angle chamber 12 is not smoothly performed.For this reason, the start-up of the engine is not smoothly performed.In order to address the above problem, it is aimed to shorten the timerequired to reach the lock phase by assisting the relative movement ofthe outer rotor 1 and the inner rotor 2 in the direction of the lockphase by the above-described spiral spring S.

(Spiral Spring)

As shown in FIG. 2B and FIG. 5, the spiral spring S operates to bias therelative rotational phase of the inner rotor 2 (driven side rotationalmember) with respect to the outer rotor 1 (driving side rotationalmember) in the direction of the lock phase in a retarded angle region Afrom the most retarded angle phase to the lock phase. In addition, thespiral spring S operates so as not to provide the biasing force in anadvanced angle region B from the lock phase to the most advanced anglephase. In this instance, it is not necessary for the spiral spring S toprovide the biasing force in the direction of the lock phase in thewhole area of the retarded angle region A. For example, the biasingforce may act from the super-retarded angle phase to near the lockphase, or the biasing force may act in the advanced angle side on thebasis of the lock phase to the advanced angle region A near the lockphase. The phase on which the biasing force of the spiral spring S actsis the predetermined phase of the embodiment disclosed here and thusbecomes a proper phase (region) suitable for the start-up of the engine(internal combustion engine).

Since the spiral spring S is formed in a spiral shape from a strap ofspring material, the thickness (dimension of the rotational shaft in thedirection of core X) can be thinned as compared with one including acoil portion such as a torsion spring. In a case where the spiral springS is installed, since a large space is not required in the direction ofthe core X of the rotational shaft, it is possible to downsize the valveopening/closing timing control device.

The outer circumference of an axial portion 10 (one example of the axialbody) of the inner rotor 2 is provided with an engaging concave portion10G having an opening width (opening width in a circumferentialdirection) of a region distance corresponding the advanced angle regionB. The front plate 6 connected to the outer rotor 1 is provided with aprotruding surface 6T protruding in the direction of the core X of therotational shaft.

The spiral spring S has a spring body 30 of a spiral shape. An engagingportion 31 is formed by bending the inner end portion of the spiralspring and is engaged to the engaging concave portion 10G, and a concavesurface 32 (one example of the support portion) is formed on an outerend portion of the spiral spring in a concaved shape in a centerdirection (core X of the rotational shaft) of the spiral spring S sothat the protruding surface 6T (one example of the support body) isinserted into the concave surface.

The front plate 6 is provided with a suppression piece 33 constituted ofa pin which abuts against the engaging portion 31 to suppress adisplacement of the engaging portion 31 in the direction of the advancedangle region B. In addition, the front plate 6 is provided with asuppression piece 34 constituted of a pin which abuts against anadjacent portion of the engaging portion 31 of the spiral spring S tosuppress a displacement of the engaging portion 31 in a direction inwhich the diameter of the spiral spring S is bulged.

In the region of the same direction on the basis of the center positionof the spiral spring S, the engaging portion 31 and the concave surface32 described above are positioned in a position to which the spring body30 is sandwiched. Further, the spiral spring S is set in such a mannerthat the distance from the engaging portion 31 to the concave surface 32is slightly longer than that from the engaging concave portion 10G tothe protruding surface 6T in a no-load free state. In addition, spacers35 are inserted into a gap of the spring body 30 in the vicinity of theouter circumference of the spiral spring S.

According to the arrangement and the feature of the spiral spring S, theabove-described biasing force is obtained by compressing the spring body30 in a radial direction so as to shorten the distance of the engagingportion 31 and the concave surface 32 slightly when the spiral spring Sis set. Consequently, the engaging portion 31 is biased in a direction(direction of the core X of the rotational shaft) of fitting it into theengaging concave portion 10G by the resilient force of the spring body30. Simultaneously, the concave surface 32 is biased in a direction ofpressing it against the protruding surface 6T. Further, the appropriategap is formed in the spring body 30 by the spacers 35. Therefore, bothends of the spiral spring S can be supported reliably and the biasingforce can provide between the outer rotor 1 and the inner rotor 2reliably.

As shown in FIG. 2A, in a state in which the engine stops at therelative phase of the inner rotor 2 with respect to the outer rotor 1which is at the super-retarded angle, an opened end portion of theengaging concave portion 10G abuts against the engaging portion 31, asshown in FIG. 2B, and the spiral spring S provides the biasing force tomove the relative rotational phase of the outer rotor 1 and the innerrotor 2 in the lock phase.

In a case where the engine stops in this state, the biasing force of thespiral spring S is provided on the outer rotor 1 and the inner rotor 2continuously through the protruding surface 6T and the axial portion 10until reaching the lock phase. As shown in FIG. 3A, if the relativelyrotational phase of the outer rotor 1 and the inner rotor 2 reaches thelock phase, the engaging portion 31 abuts against the regulation piece33, as shown in FIG. 3B. The region, on which the biasing force of thespiral spring S acts, corresponds to the retarded angle region A.

If the relative rotational phase reaches the lock phase and the engagingportion 31 abuts against the regulation piece 33, the biasing force ofthe spiral spring S does not act on the axial portion 10. Further, thelock pieces 14 of the lock mechanism L fit into the lock concaveportions 16 to reach the lock state, the stable start-up of the engineis achieved. Since the engaging portion 31 of the spiral spring S abutsagainst the suppression piece 34, it is possible to suppress thedisplacement of the spiral spring S in the bulging direction, so thatthe engaging portion 31 is not released from the engaging concaveportion 10G.

After the engine starts, as shown in FIG. 4A, in a case where the innerrotor 2 moves to the advanced angle region B in the direction of theadvanced angle, the inner rotor reaches a position in which the engagingportion 31 is spaced apart from the opened end portion of the engagingconcave portion 10G, as shown in FIG. 4B. Therefore, the biasing forceof the spiral spring S does not act on the inner rotor 2, and theappropriate relative movement is achieved by supply of the operating oilto any one of the outer rotor 1 and the inner rotor 2.

In particular, the outer end portion of the spiral spring S may beformed to have a support structure in such a manner that the front plate6 is provided with a concave portion or a hole for engagement, and theouter end portion of the spiral spring S is bent to be engaged to theconcave portion or the hole. Further, the configuration may be formed insuch a manner that a pin or the like serving as the engaging portion 31protrudes from the inner end portion of the spiral spring S to beengaged to the engaging concave portion 10G.

Since the valve opening/closing timing control device disclosed hereincludes the spiral spring S to bias the relative rotational phase ofthe outer rotor 1 and the inner rotor 2 in the lock phase direction, thespace corresponding to the coil portion such as the torsion spring isnot required, thereby suppressing the device from becoming larger.

The spiral spring S applies the biasing force in the lock phasedirection at the relative rotational phase only in a case where therelative rotational phase of the inner rotor 2 (driven side rotationalmember) to the outer rotor 1 (driving side rotational member) is in theretarded angle region A from the most retarded angle phase to near thelock phase. Consequently, if the engine starts up in the state in whichthe relative rotational phase of the inner rotor 2 to the outer rotor 1is at the most retarded angle phase, the movement of the inner rotor 2with respect to the outer rotor 1 is assisted until reaching the lockphase.

In a case where the relative rotational phase of the outer rotor 1 andthe inner rotor 2 exceeds the lock phase and is in the advanced angleregion B, the biasing force of the spiral spring S does not act, and therelative rotation is smoothly performed.

The embodiment disclosed here can be used in the whole valveopening/closing timing control devices capable of setting opening andclosing timing of any one of an intake valve and an exhaust valve of anengine.

According to an aspect of this disclosure, there is provided a valveopening/closing timing control device including a driving siderotational member synchronously rotatable with a crankshaft of aninternal combustion engine, a driven side rotational member arrangedcoaxially with the driving side rotational member in a relativelyrotational manner and integrally rotatable with a camshaft that opensand closes valves of the internal combustion engine, a retarded anglechamber and an advanced angle chamber which are formed by the drivingside rotational member and the driven side rotational member, in whichthe retarded angle chamber moves a relative rotational phase of thedriven side rotational member to the driving side rotational member in aretarded angle direction in accordance with volume increase, and theadvanced angle chamber moves the relative rotational phase in anadvanced angle direction in accordance with volume increase, a lockmechanism confining the relative rotational phase to a predeterminedlock phase, and a spiral spring providing a biasing force in apredetermined phase direction in a retarded angle region of the relativerotational phase from a most retarded angle phase to a predeterminedphase of the driven side rotational member to the driving siderotational member, and not providing the biasing force to a mostadvanced angle phase from the predetermined phase.

At the time of starting of the internal combustion engine, it ispreferable that the relative rotational phase of the driven siderotational member to the driving side rotational member is at the lockphase, but is not necessary at the lock phase. For example, it may be atthe retarded angle region side near the lock phase or at the advancedangle region side near the lock phase, on the basis of the lock phase.That is, at the time of starting of the internal combustion engine, ifthe relative rotational phase of the driven side rotational member tothe driving side rotational member is in a predetermined regionincluding the lock phase, proper starting is achieved.

In this aspect of this disclosure, if the internal combustion enginestarts up in a state in which the relative rotational phase of thedriven side rotational member to the driving side rotational member isin the retarded angle region, the relative rotational phase acts in thepredetermined phase direction by the biasing force of the spiral spring,so that the relative rotational phase is early moved in thepredetermined phase direction to enhance the starting ability of theinternal combustion engine. Further, in a case in which the relativerotational phase is more towards the advanced angle region than thepredetermined phase, the biasing force of the spiral spring does notact. In particular, since no space corresponding to the coil portion ofthe torsion spring is required by using the spiral spring, it ispossible to suppress the device from becoming larger. As a result, thevalve opening/closing timing control device can be compactly configuredwithout impairing the function of biasing the driving side rotationalmember and the driven side rotational member in the predetermined phasedirection from the most retarded angle phase.

The aspect this disclosure may include the spiral spring providing thebiasing force in the lock phase direction in the retarded angle regionof the relative rotational phase from the most retarded angle phase tothe lock phase, and not providing the biasing force to the most advancedangle phase from the lock phase.

If the internal combustion engine starts up in a state in which therelative rotational phase of the driven side rotational member to thedriving side rotational member is in the retarded angle region, therelative rotational phase acts in the lock phase direction as thepredetermined phase by the biasing force of the spiral spring, so thatthe relative rotational phase is maintained early to the lock phase toenhance the starting ability of the internal combustion engine. Further,in a case in which the relative rotational phase is in the advancedangle region than the lock phase, the biasing force of the spiral springdoes not act.

In the aspect of this disclosure, the outer circumference of ashaft-shaped body which rotates integrally with the driven siderotational member is provided with an engaging concave portion having aregion distance corresponding to the advanced angle region from the lockphase to the most advanced angle phase. An engaging portion formed bybending an inner end portion of the spiral spring is engaged to theengaging concave portion, and a support portion of an outer end portionof the spiral spring is supported by a support body which rotatesintegrally with the driving side rotational member. The engaging portionis biased in a direction of engaging the engaging concave portion by thespiral spring.

In the configuration, in accordance with the setting of the positionalrelationship between the engaging portion of the spiral spring and theengaging concave portion of the shaft-shaped body, the biasing force canact to rotate the driven side rotational member in the lock phasedirection in a case in which the relative rotational phase of the drivenside rotational member to the driving side rotational member is in theretarded angle region. Further, in a case in which the relativerotational phase of the driven side rotational member to the drivingside rotational member is in the advanced angle phase, the free rotationof the driven side rotational member is allowed. In addition, since theengaging portion is biased in a direction of a shaft core, it does notlead to problems in which the engaging portion becomes released from theengaging concave portion.

The aspect of this disclosure may include a regulation piece to restrictdisplacement of the engaging portion in the direction of the advancedangle region by abutment of the engaging portion.

In the configuration, since the position of the engaging portion isrestricted by the regulation piece, it is possible to set the range ofwhich the biasing force of the spiral spring acts.

The aspect of this disclosure may include a suppression piece abuttingagainst a portion adjacent to the engaging portion of the spiral springto suppress displacement of the engaging portion in the direction inwhich the spiral spring bulges.

In the configuration, since the suppression piece suppressesdisplacement of the engaging portion of the spiral spring in a releasingdirection from the engaging concave portion, it does not lead toproblems of the engaging portion releasing from the engaging concaveportion.

According to the aspect of this disclosure, the support portion isformed in a concave surface which is concave in the center direction ofthe spiral spring, and the support body is formed in a protrudingsurface which fits into the concave surface. The concave surface and theengaging portion may be disposed at a position in which a spring body issandwiched in a radial direction.

In the configuration, when the protruding surface is fitted into theconcave surface and the engaging portion is engaged to the engagingconcave portion, a force acts in the direction of compressing the springbody in the radial direction. By the spring load generated by the actionof the force, the biasing force is generated from the spring body sothat the protruding surface is fitted into the concave surface and theengaging portion is fitted into the engaging concave portion.Consequently, it is possible to reliably support the spiral spring andprovide the biasing force between the driving side rotational member andthe driven side rotational member reliably.

The principles, preferred embodiment and mode of operation of thepresent invention have been described in the foregoing specification.However, the invention which is intended to be protected is not to beconstrued as limited to the particular embodiments disclosed. Further,the embodiments described herein are to be regarded as illustrativerather than restrictive. Variations and changes may be made by others,and equivalents employed, without departing from the spirit of thepresent invention. Accordingly it is expressly intended that all suchvariations, changes and equivalents which fall within the spirit andscope of the present invention as defined in the claims, be embracedthereby.

1. A valve opening/closing timing control device comprising: a drivingside rotational member synchronously rotatable with a crankshaft of aninternal combustion engine; a driven side rotational member arrangedcoaxially with the driving side rotational member in a relativelyrotational manner and integrally rotatable with a camshaft that opensand closes valves of the internal combustion engine; a retarded anglechamber and an advanced angle chamber which are formed by the drivingside rotational member and the driven side rotational member, in whichthe retarded angle chamber moves a relative rotational phase of thedriven side rotational member to the driving side rotational member in aretarded angle direction in accordance with volume increase, and theadvanced angle chamber moves the relative rotational phase in anadvanced angle direction in accordance with volume increase; a lockmechanism confining the relative rotational phase to a predeterminedlock phase; and a spiral spring providing a biasing force in apredetermined phase direction in a retarded angle region of the relativerotational phase of the driven side rotational member to the drivingside rotational member from a most retarded angle phase to apredetermined phase, and not providing the biasing force to a mostadvanced angle phase from the predetermined phase.
 2. The valveopening/closing timing control device according to claim 1, wherein thespiral spring provides the biasing force in the predetermined lock phasedirection in the retarded angle region of the relative rotational phasefrom the most retarded angle phase to the predetermined lock phase, anddoes not provide the biasing force to the most advanced angle phase fromthe predetermined lock phase.
 3. The valve opening/closing timingcontrol device according to claim 2, wherein an outer circumference of ashaft-shaped body which rotates integrally with the driven siderotational member is provided with an engaging concave portion having aregion distance corresponding to the advanced angle region from thepredetermined lock phase to the most advanced angle phase; an engagingportion formed by bending an inner end portion of the spiral spring isengaged to the engaging concave portion, and a support portion of anouter end portion of the spiral spring is supported by a support bodywhich rotates integrally with the driving side rotational member; andthe engaging portion is biased in a direction of engaging the engagingconcave portion by the spiral spring.
 4. The valve opening/closingtiming control device according to claim 3, further comprising aregulation piece to regulate displacement of the engaging portion in adirection of the advanced angle region by abutment of the engagingportion.
 5. The valve opening/closing timing control device according toclaim 3, further comprising a suppression piece abutting against tosuppress displacement of the engaging portion in a direction in whichthe spiral spring bulges.
 6. The valve opening/closing timing controldevice according to claim 4, further comprising a suppression piece tosuppress displacement of the engaging portion in a direction in whichthe spiral spring bulges.
 7. The valve opening/closing timing controldevice according to claim 3, wherein the support portion is formed in aconcave surface which is concave in a center direction of the spiralspring, and the support body is formed in a protruding surface whichfits into the concave surface; and the concave surface and the engagingportion are disposed at a position in which a spring body is sandwichedin a radial direction.
 8. The valve opening/closing timing controldevice according to claim 4, wherein the support portion is formed in aconcave surface which is concave in a center direction of the spiralspring, and the support body is formed in a protruding surface whichfits into the concave surface; and the concave surface and the engagingportion are disposed at a position in which a spring body is sandwichedin a radial direction.
 9. The valve opening/closing timing controldevice according to claim 5, wherein the support portion is formed in aconcave surface which is concave in a center direction of the spiralspring, and the support body is formed in a protruding surface whichfits into the concave surface; and the concave surface and the engagingportion are disposed at a position in which a spring body is sandwichedin a radial direction.
 10. The valve opening/closing timing controldevice according to claim 6, wherein the support portion is formed in aconcave surface which is concave in a center direction of the spiralspring, and the support body is formed in a protruding surface whichfits into the concave surface; and the concave surface and the engagingportion are disposed at a position in which a spring body is sandwichedin a radial direction.